998 resultados para Löytönen, Markku: Koillisväylän löytäjä. Tutkimusmatkaaja Adolf Erik Nordenskiöld Jäämerellä
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Two years of harmonized aerosol number size distribution data from 24 European field monitoring sites have been analysed. The results give a comprehensive overview of the European near surface aerosol particle number concentrations and number size distributions between 30 and 500 nm of dry particle diameter. Spatial and temporal distribution of aerosols in the particle sizes most important for climate applications are presented. We also analyse the annual, weekly and diurnal cycles of the aerosol number concentrations, provide log-normal fitting parameters for median number size distributions, and give guidance notes for data users. Emphasis is placed on the usability of results within the aerosol modelling community. We also show that the aerosol number concentrations of Aitken and accumulation mode particles (with 100 nm dry diameter as a cut-off between modes) are related, although there is significant variation in the ratios of the modal number concentrations. Different aerosol and station types are distinguished from this data and this methodology has potential for further categorization of stations aerosol number size distribution types. The European submicron aerosol was divided into characteristic types: Central European aerosol, characterized by single mode median size distributions, unimodal number concentration histograms and low variability in CCN-sized aerosol number concentrations; Nordic aerosol with low number concentrations, although showing pronounced seasonal variation of especially Aitken mode particles; Mountain sites (altitude over 1000 m a.s.l.) with a strong seasonal cycle in aerosol number concentrations, high variability, and very low median number concentrations. Southern and Western European regions had fewer stations, which decreases the regional coverage of these results. Aerosol number concentrations over the Britain and Ireland had very high variance and there are indications of mixed air masses from several source regions; the Mediterranean aerosol exhibit high seasonality, and a strong accumulation mode in the summer. The greatest concentrations were observed at the Ispra station in Northern Italy with high accumulation mode number concentrations in the winter. The aerosol number concentrations at the Arctic station Zeppelin in Ny-Ã…lesund in Svalbard have also a strong seasonal cycle, with greater concentrations of accumulation mode particles in winter, and dominating summer Aitken mode indicating more recently formed particles. Observed particles did not show any statistically significant regional work-week or weekday related variation in number concentrations studied. Analysis products are made for open-access to the research community, available in a freely accessible internet site. The results give to the modelling community a reliable, easy-to-use and freely available comparison dataset of aerosol size distributions.
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Alanimeke kannessa ja esiössä: en reflexstudie.
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Kannen signeeraus: Arthur Högstedt.
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La primera tarea de un Instituto nuevo que se dedica a la investigación cientÃfica pura dentro de un territorio poco conocido es elaborar un catálogo de las riquezas naturales que constituyen la fauna y la flora de dicho paÃs. Por esta razón es la tarea básica de nuestro Instituto Tropical de Investigaciones CientÃficas de El Salvador investigar la fauna y flora un mapa geológico del paÃs. Las clases de los vertebrados están terminadas o actualmente en trabajo, tenemos ya en nuestras manos los manuscritos acerca de las aves, anfibios y reptiles de El Salvador; actualmente se están estudiando los mamÃferos un especialista en peces, la última clase de vertebrados, llegara a principios del año entrante. También diferentes grupos de los invertebrados, como por ejemplo los caracoles terrestres y varios grupos de insectos están ya investigados. En cuanto a la flora, se está elaborando una descripción de las especies de las catorce familias de la fanerógamas pentacÃclicas, a las cuales pertenecen las orquÃdeas y las bromeliáceas. El trabajo de la fauna y flora tiene dos fines: describir las especies nuevas recién descubiertas y comprobar la presencia de las especies ya conocidas que hasta ahora no se habÃan descrito.
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Entre los miles de lepidópteros coleccionados por el Dr. Adolf Zilch durante su estancia en El Salvador se hallaban 204 sphingidae de 33 especies donde no se anota diferentemente los animales proceden de San Salvador. Todos fueron coleccionados mediante captura por luz, por ofrecerse precisamente buena ocasión para aquel método en el Instituto Tropical de Investigaciones CientÃficas de El Salvador. Los faroles colocados alrededor del Instituto atraÃan con su luz resplandeciente masas de insectos noche tras noche y el Dr. Zilch los coleccionaba cada tres o cuatro horas en la pared iluminada del edificio. En los anales del Instituto de BiologÃa de 1942, Carlos especificó para México 154 especies de sphingidae.
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Hasta hoy dÃa no se habÃan descrito de El Salvador, coleópteros de la familia de los Girinidos. Por eso me ha alegrado mucho obtener del Museo Senckenberg, en Francfort A. M. Una colección de estos coleópteros, coleccionados por el Dr. Zilch durante sus viajes de exploración, en El Salvador, en el año 1951. El material investigado contenÃa 7 especies, entre las cuales se encontraban dos Gyretes hasta ahora desconocidos. Simultáneamente recibà del museo zoológico de Vienna tres ejemplares de Dineutus sublimatus que se habÃan coleccionado en 1877 en El Salvador.
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Quantifying global patterns of terrestrial nitrogen (N) cycling is central to predicting future patterns of primary productivity, carbon sequestration, nutrient fluxes to aquatic systems, and climate forcing. With limited direct measures of soil N cycling at the global scale, syntheses of the (15)N:(14)N ratio of soil organic matter across climate gradients provide key insights into understanding global patterns of N cycling. In synthesizing data from over 6000 soil samples, we show strong global relationships among soil N isotopes, mean annual temperature (MAT), mean annual precipitation (MAP), and the concentrations of organic carbon and clay in soil. In both hot ecosystems and dry ecosystems, soil organic matter was more enriched in (15)N than in corresponding cold ecosystems or wet ecosystems. Below a MAT of 9.8°C, soil δ(15)N was invariant with MAT. At the global scale, soil organic C concentrations also declined with increasing MAT and decreasing MAP. After standardizing for variation among mineral soils in soil C and clay concentrations, soil δ(15)N showed no consistent trends across global climate and latitudinal gradients. Our analyses could place new constraints on interpretations of patterns of ecosystem N cycling and global budgets of gaseous N loss.
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The immunogenic properties of cysteine proteases obtained from excretory/secretory products (ES) of Haemonchus contortus were investigated with a fraction purified with a recombinant H. contortus cystatin affinity column. The enrichment of H. contortus ES for cysteine protease was confirmed with substrate SDS-PAGE gels since the cystatin-binding fraction activity was three times higher than total ES, despite representing only 3% of total ES. This activity was inhibited by a specific cysteine protease inhibitor (E64) and by recombinant cystatin. The one-dimensional profile of the cystatin-binding fraction displayed a single band with a molecular mass of 43 kDa. Mass spectrometry showed this to be AC-5, a cathepsin B-like cysteine protease which had not been identified in ES products of H. contortus before. The cystatin binding fraction was tested as an immunogen in lambs which were vaccinated three times (week 0, 2.5 and 5), challenged with 10 000 L3 H. contortus (week 6) before necropsy and compared to unvaccinated challenge controls and another group given total ES (n = 10 per group). The group vaccinated with cystatin-binding proteins showed 36% and 32% mean worm burden and eggs per gram of faeces (EPG) reductions, respectively, compared to the controls but total ES was almost without effect. After challenge the cystatin-binding proteins induced significantly higher local and systemic ES specific IgA and IgG responses.
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Pomegranate [Punica granatum (Punicaceae)] is characterized by having two types of flowers on the same tree: hermaphroditic bisexual flowers and functionally male flowers. This condition, defined as functional andromonoecy, can result in decreased yields resulting from the inability of male flowers to set fruit. Morphological and histological analyses of bisexual and male flowers were conducted using light and scanning electron microscopy (SEM) to characterize the different flower types observed in pomegranate plants and to better understand their developmental differences. Bisexual flowers had a discoid stigma covered with copious exudate, elongated stigmatic papillae, a single elongate style, and numerous stamens inserted on the inner wall of the calyx tube. Using fluorescence staining, high numbers of pollen tubes were observed growing through a central stylar canal. Ovules were numerous, elliptical, and anatropous. In contrast, male flowers had reduced female parts and exhibited shortened pistils of variable heights. Stigmatic papillae of male flowers had little exudate yet supported pollen germination. However, pollen tubes were rarely observed in styles. Ovules in male flowers were rudimentary and exhibited various stages of degeneration. Pollen from both types of flowers was of similar size, approximate to 20 mu m, and exhibited similar percent germination using in vitro germination assays. Pollen germination was strongly influenced by temperature. Maximal germination (greater than 74%) was obtained at 25 and 35 degrees C; pollen germination was significantly lower at 15 degrees C (58%) and 5 degrees C (10%).
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Estimation of Taylor`s power law for species abundance data may be performed by linear regression of the log empirical variances on the log means, but this method suffers from a problem of bias for sparse data. We show that the bias may be reduced by using a bias-corrected Pearson estimating function. Furthermore, we investigate a more general regression model allowing for site-specific covariates. This method may be efficiently implemented using a Newton scoring algorithm, with standard errors calculated from the inverse Godambe information matrix. The method is applied to a set of biomass data for benthic macrofauna from two Danish estuaries. (C) 2011 Elsevier B.V. All rights reserved.